The power consumed by a microprocessor is transformed into heat. A pair of microprocessors mounted on a single motherboard can draw 200-400 watts or more of power. If that power draw is multiplied by several thousand (or tens of thousands) to account for the computers in a data center, the potential for heat generation can be appreciated. Not only must a data center operator pay for electricity to operate the computers, it must also pay to cool the computers. The cost of removing heat may be a major cost of operating large data centers.
In addition, components of a computer, such as a microprocessor, memory or disk drive, are subject to breakdown when subjected to high temperatures. A fan can provide a steady flow of air across the components of the computer to carry away heat, and heat sinks can be attached to some components, particularly the microprocessor, to improve thermal transfer to the surrounding air. Despite these precautions, computer components can still overheat and fail, particularly when operating at high utilization.